With development of the wireless communication, there are more and more demands for various data services in mobile environments. The fourth generation (“4G”) and beyond wireless communication standards allow higher transmission rate and wider bandwidth. In the meantime, the peak to average power ratio (“PAPR”) of the signals is relatively high. Generally speaking, high PAPR will put negative impact on the efficiency of radio frequency (“RF”) power amplifier (“RFPA”) and thus degrade the system performance.
Envelope tracking (“ET”) and envelope elimination and restoration (“EER”) have been proposed in order to provide high efficiency of RFPA. Power supply modulation is an important factor for the RFPA. The RF envelope can be tracked and input into a power supply modulator. According to the RF envelope, the modulator provides dynamic supply output into the RFPA so as to amplify the RF signal adaptively. In order to perform efficient and effective signal amplification, especially to the signals with high PARA, there is a need in art for a power supply modulation solution which is capable of providing high efficiency and bandwidth without increasing the circuitry complexity of the modulator.